What are some things i can try to do to fix my nav it keeps showing me off center sometimes, for example when i am driving on a strate road it will be showing that the road is strate and then all of the sudden it will show me a little of center to the left or right and the entire screen will shit a little bit, what can i try to do to fix this, the main problem is that it shows me just a little off center of the road?

Make sure your VSS is hooked up, make sure your antenna has a clear view to the sats and is not getting interference from anything else near it, clear out the calibration settings and see if it helps.